This is an example of a DDNS configuration running on Fedora Core 1 Linux.

http://fedoranews.org/contributors/derek_pienaar/ddns http://ops.ietf.org/dns/dynupd/secure-ddns-howto.html DHCPNotes are well worth reading.

DynamicDNS (DDNS) makes adding a new computer to my network as simple as plugging it into my switch. The new client tells the server what its host name is, and the server allocates it an address (DHCP) and lets the rest of the network know (DNS). No configuration at the server is required! (It's the next best thing to ZeroConf?.) I like having this running as I was told it "couldn't be done" :-D.

The "secret key" is generated with dns-keygen.

/etc/named.conf

// Dave's own hacked named.conf // with dynamic DNS :-D

options {

directory "/var/named"; allow-query {

192.168.10/24; 192.168.12/24; localhost;

};

// forward only; // forward first;

forwarders {

210.55.24.14; 210.55.24.8;

};

};

controls {

inet 127.0.0.1 allow { localhost; } keys { rndckey; };

};

// Master DNS servers zone "." IN {

type hint; file "named.ca";

};

// Localhost addresses zone "localhost" IN {

type master; file "localhost.zone"; allow-update { none; };

}; zone "0.0.127.in-addr.arpa" IN {

type master; file "named.local"; allow-update { none; };

};

// Magic key which lets DHCP update DNS key "DHCP-UPDATER" {

algorithm hmac-md5; secret "ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff";

};

// Home network zone "invermay" {

type master; notify no; file "invermay.zone"; allow-update { key DHCP-UPDATER; };

};

// Reverse name resolution for home network zone "12.168.192.in-addr.arpa" {

type master; notify no; file "named.invermay"; allow-update { key DHCP-UPDATER; };

};

// Reverse name resolution for wireless link zone "10.168.192.in-addr.arpa" {

type master; notify no; file "named.invermay.decknet"; allow-update { key DHCP-UPDATER; };

};

include "/etc/rndc.key";

/etc/dhcpd.conf

1. Dave's own hacked dhcpd.conf
2. with dynamic DNS :-D
3. Don't forget command line options are in /etc/sysconfig/dhcpd

ddns-domainname "invermay"; ddns-update-style interim;

1. ignore client-updates;
2. ddns-updates off;
3. Magic key which lets DHCP update DNS

key "DHCP-UPDATER" {

algorithm hmac-md5; secret "ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff";

};

1. DNS zones to update

zone invermay. {

primary 127.0.0.1; key DHCP-UPDATER;

} zone 12.168.192.in-addr.arpa. {

primary 192.168.12.254; key DHCP-UPDATER;

} zone 10.168.192.in-addr.arpa. {

primary 192.168.10.254; key DHCP-UPDATER;

}

1. Home network on eth2

subnet 192.168.12.0 netmask 255.255.255.0 {

1. Default gateway

option routers 192.168.12.254; option subnet-mask 255.255.255.0;

option domain-name "invermay"; option domain-name-servers 192.168.12.254;

range 192.168.12.128 192.168.12.254; default-lease-time 86400; # 1 day max-lease-time 259200; # 3 days

authoritative; ddns-updates on;

}

1. Wireless link on eth0

subnet 192.168.10.0 netmask 255.255.255.0 {

1. Default gateway

option routers 192.168.10.254; option subnet-mask 255.255.255.0;

option domain-name "invermay"; option domain-name-servers 192.168.10.254;

range 192.168.10.128 192.168.10.254; default-lease-time 86400; # 1 day max-lease-time 259200; # 3 days

authoritative; ddns-updates on;

}

/var/named/invermay.zone

$ORIGIN . $TTL 604800 ; 1 week invermay IN SOA rata.invermay. root.rata.invermay. (

107 ; serial 28800 ; refresh (8 hours) 14400 ; retry (4 hours) 3024000 ; expire (5 weeks) 86400 ; minimum (1 day) )

NS rata.invermay.

$ORIGIN invermay. $TTL 129600 ; 1 day 12 hours feijoa A 192.168.10.253

TXT "3128380ff01e7006b0688a5d32bba2d551"

$TTL 604800 ; 1 week localhost A 127.0.0.1 ollienet A 192.168.12.254 rata A 192.168.12.254 tuxnet A 192.168.12.254

/var/named/localhost.zone

$TTL 86400 $ORIGIN localhost. @ 1D IN SOA @ root (

42 ; serial (d. adams) 3H ; refresh 15M ; retry 1W ; expiry 1D ) ; minimum

1D IN NS @ 1D IN A 127.0.0.1

/var/named/named.invermay

$ORIGIN . $TTL 604800 ; 1 week 12.168.192.in-addr.arpa IN SOA rata.invermay. root.rata.invermay. (

104 ; serial 28800 ; refresh (8 hours) 14400 ; retry (4 hours) 3024000 ; expire (5 weeks) 86400 ; minimum (1 day) )

NS rata.invermay.

$ORIGIN 12.168.192.in-addr.arpa. 254 PTR rata.invermay.

/var/named/named/named.invermay.decknet

$ORIGIN . $TTL 86400 ; 1 day 10.168.192.in-addr.arpa IN SOA rata.invermay. root.rata.invermay. (

101 ; serial 28800 ; refresh (8 hours) 14400 ; retry (4 hours) 3024000 ; expire (5 weeks) 86400 ; minimum (1 day) )

NS rata.invermay.

$ORIGIN 10.168.192.in-addr.arpa. $TTL 129600 ; 1 day 12 hours 253 PTR feijoa.invermay. $TTL 86400 ; 1 day 254 PTR rata.invermay.

/var/named/named.local

$TTL 86400 @ IN SOA localhost. root.localhost. (

1997022700 ; Serial 28800 ; Refresh 14400 ; Retry 3600000 ; Expire 86400 ) ; Minimum

IN NS localhost.

1 IN PTR localhost.

Arghhh!!!!

// just listen internally

listen-on {

192.168.10/24; 192.168.12/24;

};

Seemed like a good idea, but screwed up dynamic updating for some reason. Kept getting connection refused messages. And I'd changed a few things so it took me all day to figure out.

NB: this is taken from www.linuxsoftware.co.nz/wiki/DynamicDNS